<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
<div id="app">
    <ol>
        <todo-item></todo-item>
    </ol>
</div>
</body>
<script src="https://unpkg.com/vue"></script>
<script>
    Vue.component('todo-item',{
        template:'<li>This is a new item.</li>'
    });
    var app=new Vue({
        el:'#app'
    });
</script>
</html>